Core drill



s. P. LEWIS 3,299,971

CORE DRILL 2 Sheets-Sheet l Jan. 24, 1967 Filed Aug. 6, 1964 Jan. 24,1967 s. P. LEWIS 3,299,971

CORE DRILL Filed Aug. 6, 1964 2 Sheets-Sheet 2 JNVENTOR.

SAMUEL R EW/5 BY 4l ATTORNEY United States Patent O 3,299,971 CORE DRILLSamuel l. Lewis, Phillipshurg, NJ., assignor to Ingersoll- Rand Company,New York, N.Y., a corporation of New Jersey Filed Aug. 6, 1964, Ser. No.387,936 11 Claims. (Cl. 175-92) This invention relates to kerf or coredrills and more specifically to a down-the-hole core drill of the impactor percussive type.

Conventionally, core drilling is achieved by rotary drilling apparatuseswhich can only obtain a relatively short length of core before it isnecessary t remove it from the hole. In addition, these rotary drillingapparatuses employ drilling mud fiuid to achieve drilling, which fluidis expensive.

Accordingly, it is an object of this invention to provide a core drillwhich employs air as a drilling fiuid and provides a continuous core.

Another object of the present invention is to provide a core drill inwhich the drilling power or energy is produced within the hole beingbored.

A further object of this invention is to provide a downthe-holepercussive drill capable of boring a continuous core.

The foregoing and other objects are carried out by providing a coredrill which has a casing with a drill bit mounted within one end of thecasing for limited axial movement relative to the casing. A tubularguide is mounted within the casing and dimensioned to be spaced from thecasing to provide an annular space between the casing and the coreguide. A hollow tubular piston is mounted within the annular space foraxial movement therein. The annular space also provides passage meansfor delivering pressurized fluid to the piston means. Valve means aredisposed within the annular space for controlling the flow ofpressurized fluid to opposite sides of the piston to cause the piston todeliver an impact to the drill bit.

In view of the foregoing, a novel core drill is contemplated, which coredrill comprises an impact drill bit assembly suspended from a hollowdrill string. The impact drill bit assembly consists of a piston orhammer disposed within a cylinder for reciprocating and intermittentimpaction against a calyx bit or cutter. Means for conducting thecompressed air to the drill bit assembly and distributing the airalternately to the front and back ends of the cylinder is provided toeffect the reciprocation of the hammer.

A feature of the present invention is the tubular configuration of thehammer which is disposed around a tubular member defining a corepassageway through the drill bit assembly and drill string so that acontinuous core is produced and removed from the hole being bored.

The invention will be more fully understood from the following detaileddescription thereof when considered in connection with the accompanyingdrawings in which:

FIG. l is a longitudinal, sectional view through the upper portion ofthe core drill according to this invention and joined to the lowerportion of the core drill along line A A of FIG. 1A;

FIG. 1A is a longitudinal, sectional view of the lower portion ofthecore drill shown in FIG. l and joined to the upper portion along line AA of FIG. l;

FIGS. 2, 3, 4, and 5 are cross-sectional views taken along lines 2 2, 33, 4 4, and 5 5, respectively, of FIG. l;

FIGS. 6 and 7 are cross-sectional views taken along lines 6 6 and 7 7,respectively, of FIG. 1A; and

FIG.l 8 is a fragmentary view, on a greatly enlarged scale, of the appervalve shown in FIG. l.

Mice

Now referring to the drawings, the reference number 10 designates theimpact drill bit assembly connected to the distal end of a drill string12 which consists of a plurality of endwise-connected hollow drill rods14.

The impact drill bit assembly 10 comprises a tubular wear sleeve orcasing 16 to which is connected a tubular backhead member 18.Concentrically disposed within wear sleeve 16 is a hollow cylindricalmember 20 which defines with a tubular core guide member 22 of smallerdiameter than cylindrical member 20 an annular piston or hammer chamber24. Disposed for axial reciprocation within chamber 24 is a piston orhammer 26. Held within the lower end of wear sleeve 16 is a calyx drillbit or cutter 28 of the rotary-percussive type and disposed to besubjected to intermittent impacts by hammer 26.

Each of the drill rods 14 includes a tu-bular core guide 30 which iscoaxially supported in spaced relationship to the inner surface of thedrill rod by a plurality of axially spaced, annular spacing rings 32(only one Vof which is shown in FIG. l). Drill rod 14 and core guide 30define therebetween an annular fluid passageway 34. Spacing rings 32 areprovided with a plurality of peripherally spaced openings 36 to permitthe passage of the fluid through the fluid passageway 34. The lower endportion 38 of each of the core guides 30 of each drill rod 14 is ofreduced diameter and is fiared outwardly adjacent its end. The endportion 38 is provided with a plurality of splits 4i) to impartresiliency to the end portion 38 so that the end poltion 38 willcompress as it is inserted past an internal annular restriction 42formed in the upper end portion 44 of the next lower tubular core guide30, the upper end portion 44 of each core guide 30 being of the sameconstruction as shown in FIG. l for tubular core guide member 22. AnO-ring seal 46 is carried in a groove in annular restriction 42 to sealthe interstices between the telescoping end portions 38 and 44 ofadjacent tubular core guides 3l) and the endmost tubular core guide 30and core guide mem-ber 22. The uppermost drill rod 14 is suitablyconnected to communicate with a source of pressurized fluid as, forexample, an air compressor and thereby receive and conduct thepressurized fluid via annular fluid passageway 34 to impact drill bitassembly 10.

As best shown in FIGS. l and 2, backhead 18 is provided with a pluralityof circumferentially spaced holes 49 to pass the pressurized fluid to acontrol valve assembly 50. Backhead 18 has reduced diameter, threadedopposite end portions 52 and 54 for connection with internally threadedend portion 56 of drill rod 14 and internally threaded end portion 58 ofwear sleeve 16. Backhead 18 is also provided with internal threads 53which mesh with threads 31 on core guide member 22 for connection of thelatter with backhead 18. Backhead 18 is counterbored adjacent its endportion 54 to define with control valve 50 an annular chamber 55.

Control valve assembly 50 comprises an annular, ringshaped valve chest60, an annular fiapper valve 62, and an annular, ring-shaped valve seat64 disposed ybetween tubular core guide member 22 and wear sleeve 16.Valve chest 60 and Valve seat 64 are clamped in abutment against eachother between end portion 54 of backhead 18 and the end of cylindricalmember 20. Valve chest 60 is provided with an axial recess 66 in one endthereof, in which recess a fiapper valve 62 is housed. A plurality ofperipherally spaced holes 68 provide for the fiow of the pressurizedfluid from annular cham-ber 55 into recess 66.

As best shown in FIGS. 1, 3, and 4, valve seat 64 has a plurality offluid inlet ports 70 which communicate at one end with an arcuate-shapedslot 72 (see FIG. 3) in the upper surface of the valve seat and at theopposite end communicate with the upper end portion of hammer cham-ber24. In the upper surface of valve seat 64,

diametrically opposite arcuate-shaped slot 72, an arcuateshaped recess74 is formed to provide for the ow of the pressurized Huid to the frontend of hammer chamber 24 as hereinafter described. As Abest shown inFIGS. 1 and 4, a port 76 is provided in valve seat 64 to convey thepressurized uid from recess 74 into a longitudinally extendingpassageway 78 dened between a groove in the inner surface of wear sleeve16 and the outer surfaces of valve seat 64 and cylindrical member 20.

As shown in FIGS. lA and 7, passageway 78 communi- Cates at its lowerend with a hammer return port 80* which communicates with the lower endof hammer chamber 24 via an annular recess 81 in wear sleeve 16 and theradial grooves 82 lformed in the upper surface portion of drill bit 28.The pressurized fluid -owing into hammer chamber 24 by way of port 80,annular recess 81, and radial grooves 82 effects the movement of piston26 rearwardly; that is, in a direction toward control valve assembly 50.The pressurized fluid is exhausted from the lower portion of hammerchamber 24 through an exhaust port 84 consisting of a hole 86, anarcuate groove 87 in cylindrical member 20, and a hole 88 in wear sleeve16. Similarly, the pressurized uid is exhausted from the upper part ofhammer chamber 24 through an exhaust port 85 (see FIG. l).

The apper valve 62 rocks or tilts in response to the differentialpressure across the valve so as to `control the flow of the pressurizeduid alternately through ports 70 and port 76 and, hence, alternately tothe front and the rear portions of hammer chamber 24 and thereby causethe reciprocation of hammer 26.

As shown in FIG. lA, cylindrical mem-ber 20 is secured within wearsleeve 16 by a retaining ring 90 and in abutment against a bit retainingring 92.

Core drill bit 28 comprises a head portion 94 integrally formed with ashank portion 96 and having an axial bore 98 therethrough which iscoextensive and communicates with the interior of cylindrical `guidemember 22. The upper end of shank portion 96 is counterbored at 100 toreceive the lower end of guide member 22 therein. The outer surface ofshank portion 96 is provided with longitudinally extending splines 102which mesh with cornplementary splines 104 of a drill chuck 106. Chuck106 is threadably secured at 108 to the lower end of wear sleeve 16. Thespline interconnection between chuck 106 and drill bit 28 permits thelatter to be rotated simultaneous with the axial movement relative tochuck 106 and wear sleeve 16. The extent of yrelative axial movement ofdrill bit 28 in a forward direction is limited by the abutment of anannular shoulder 107 formed on shank portion 96 and bit retaining ring92. The movement of drill bit 28 in a rearward direction is limited bythe abutment of the end of splines 102 against retaining ring 92. Theannular working face of head portion 94 may be constructed with aplurality of peripherally spaced tungsten carbide inserts 110 forproviding the bit with wear-resistant cutting edges.

The above-described drill string 12 and impact drill bit assembly areconnected aboveground to a suitable motor means for rotating,longitudinally feeding, and supplying the pressurized fluid to drillstring 12 and impact drill bit assembly 10. A typical motor means may beof the type shown in U.S. patent application, Serial No. 294,962, iiledJuly 15, 1963, now U.S. Patent No. 3,155,-

179, and shown in U.S. Patent No. 2,985,249. The motor means may beconstructed so as to provide the movement of the core through the motormeans as disclosed in U.S. patent application, Serial No. 173,389, datedFebruary 15, 1962, now U.S. Patent No. 3,154,158. Other suitable` meansfor continuously removing the core being bored may be provided withoutdeparting from the scope and spirit of this invention.

In the operation of the core drill according to this invention,pressurized fluid, such as compressed air, is supplied to annularpassageway 34 of the uppermost drill rod 14 by suitable means, notshown. The pressurized fluid ows from passageway 34 of the drill rod 14,which is connected to impact dri'll bit assembly 10, into holes 49 inbackhead 18. From backhead 18 the pressurized uid flows into annularchamber 55 and thence into holes 68 of valve chest 60. As shown in FIGS.l and lA, the position of flapper valve 62 is such that the pressurizeduid is prevented from owing into the rear of hammer chamber 24 by reasonof the diiferential pressure across the flapper valve wit-h chamber 24in communication with a lowpressure space through exhaust port 85.However, flapper valve 62 is positioned to permit the Iflow of thepressurized fluid from recess 66 into arcuate recess 74 and into port76. From port 76 the pressurized iluid flows through passageway 78 intoport 80 and thence into the lower portion of hammer chamber 24 viagrooves 82. The ow of the pressurized fluid into the lower e-nd ofhammer chamber 24, which uid acts on the end surface of hammer 26,forces the hammer rearwardly in hammer chamber 24 until exhaust port 84comes into communication with the lower portion of the hammer chamber.As the hammer moves rearwardly exhaust port closes; and, vas thepressurized uid in the upper portion of the hammer chamber iscompressed, a pressure imbalance Vacross flapper valve 62 is createdthrough ports 70 and arcuate slot 72. This imbalance causes the flappervalve to tilt to a position closing recess 74 and port '76 and openingthe upper portion of hammer chamber 24 to the pressurized fluid throughports 70 and slot 72. The flow of the pressurized fluid into the upperpart of Ihammer chamber 24 drives hammer 26 forwardly to impact againstthe end of shank portion 96 of drill bit 28. When hammer 26 travels asufficient distance to expose exhaust port 85, the pressurized uid isexhausted from chamber 24 to the interior of the hole being bored. Withthe flapper valve controlling the flow of the pressurized fluidalternately to the front and the rear portions of hammer chamber 24,hammer 26 intermittently delivers impact blows to drill bit 28.Simultaneous with the impacting of drill bit 28, drill bit 28, throughdrill string 12, is rotated by conventional means (not shown).

As the hole is bored, a core 111 (see FIG. 1A) is formed and, Ias the`boring progresses, the core is guided and retained by guide member 22and core guides 30 of drill rods 14.

To provide for continuously carrying away the core, the pressurizedexhaust fluid is discharged into the bored hole through exhaust ports 84and 85. To insure the movement of the pressurized fluid down the boredhole, anto `axial bore 98, through drill Ibit 28 and into the intenorsof core guides 30, additional pressurized uid may be lntroduced into thehole at the ground surface through a hood (not shown) placed about thedrill string and over the bored hole.

To reduce the frictional resistance to the reciprocation of hammer 26,the inner surface and the outer surface between the opposite endportions of the hammer may Ibe undercut or recessed at 112 and 114,respectively, as shown.

It is believed now readily apparent that a novel core drill which has animpact motor means in the hole being bored and provides for a continuousextraction of a core has been provided.

Although but one embodiment of the invention has been illustrated anddescribed in detail, it is to be expressly understood that the inventionis not limited thereto. Various changes can fbe made in the arrangementof parts without departing from the spirit and scope of the invention,as the .same will now be understood by those skilled inthe art.

I claim:

1. A core drill comprising:

an elongated casing;

a drill fbit mounted within one end of said casing for rotation withsaid casing and limited axial movement relative to said casing;

said casing being dimensioned to follow said drill bit down a hole beingdrilled;

tubular means mounted within said casing to provide a continuouslyunobstructed passage `between the drill bit and the top of said casingand dimensioned lto be spaced from said casing to define -an annularspace;

piston means mounted for axial movement within said annular space;

passage means for delivering pressurized fiuid to said piston means; and

annular valve means disposed within said annular space for controllingthe flow of pressurized fluid to opposite sides of said piston means tocause said piston means to deliver an impact to said drill bit.

2. The core drill of claim 1 wherein said drill bit is hollow.

3. The core drill of claim 1 wherein said piston means is tubular inconfiguration.

4. The core drill of claim 1 wherein said valve means includes a valveseat, a valve chest having a passage therethrough and an annular fiappervalve disposed between said valve seat and valve chest.

5. The core drill of claim 4 further including an annular sleeve mountedwithin said annular space between said casing and piston means andproviding a passage Iaround said piston means for conducting pressurizedfiuid Ito one end of said piston means for raising said piston means.

6. The core drill of claim 5 wherein said valve seat has a passage forconducting pressurized fiuid to the passage around said piston means.

7. The core drill of claim 6 wherein said valve seat has a secondpassage therethrough for conducting pressurized fluid to the other endof said piston means and said casing is provided with exhaust ports forpassing spent pressurized fiuid into the hole being drilled.

8. A core drill comprising:

(a) a drill rod,

(b) an elongated casing means connected to said drill rod,

(c) a drill bit connected to the distal end of said casing means forconjoined rotation with the latter and limited axial movement relativeto the casing means,

(d) said drill bit having an axial bore therethrough,

(e) a tube means disposed in said drill rod and said casing means inspaced relation with the latter and coextensive with the axial bore insaid drill bit to receive and guide a core being bored,

(f) a valve disposed in the space between the casing means and said tubemeans,

(g) said tube means in said casing means defining with the latter, thedrill bit, and the valve, an annular piston chamber,

(h) a piston disposed for reciprocation in said piston chamber,

(i) a source of pressurized fiuid connected to said drill rod to deliverthe pressurized iiuid to the space defined between the drill rod and thetube means,

(j) first passage means in said valve for communicating said spacebetween the drill rod and the tube means with one end of said pistonchamber,

(k) second passage means in said valve -for communicating said spacebetween the drill rod and the tube means with the other end of saidpiston chamber, and

(l) vexhaust ports communicating with the opposite ends of the pistonchamber to pass spent pressurized fiuid from the piston chamber into thehole being bored,

(m) said valve means functioning to alternately open and close saidfirst and said second passage means and thereby cause the piston toreciprocate and intermittently strike the drill bit.

9. The apparatus of claim 8 wherein said casing means comprises a wearsleeve and a piston-cylinder lining the Wear sleeve.

10. A core drill comprising:

(a) a drill rod, l

(b) an elongated casing connected to said drill rod for conjoinedrotation with the latter,

(c) a hollow drill bit connected to the distal end of the casing forconjoined rotation with the latter and limited, relative axial movementwith respect to the casing,

(d) a hollow cylindrical member disposed to line the interior surface ofsaid casing,

(e) a tube means disposed in said hollow cylindrical member anddimensioned to be spaced from the latter to define an annular space,

(f) said tube means being coextensive with the interior of said hollowdrill bit to receive a core being bored by the latter,

(g) a control valve disposed in said annular space and axially spacedfrom the drill Ibit to define with the latter, the tube means, and thecylindrical member, a piston chamber,

(h) a tubular piston disposed in said piston chamber Vfor reciprocationwithin the latter,

(i) means for providing the flow of the pressurized fiuid through saiddrill rod to said control valve, (j) first passage means in said controlvalve for passing the pressurized fiuid to one end of said pistonchamber,

(k) second passage means in said control valve for passing thepressurized fiuid to the opposite end of said piston chamber, and

(l) exhaust ports at the opposite end portions of said piston chamber topass spent pressurized iiuid into the hole being bored,

(m) said control valve functioning in response to the differentialpressure thereacross to alternately open and close said first and saidsecond passage means and thereby cause the piston to reciprocate andstrike the drill bit.

11. A core drill comprising:

(a) a casing,

(b) a hollow cylindrical member secured coaxially within said casing,

(c) a drill bit having an axial bore therethrough and connected `forlimited reciprocative movement to said casing,

(d) a core guide member disposed in and secured to said casing with theouter surface thereof defining with the inner surface of said hollowcylindrical member an annular piston chamber,

(e) a tubular -hammer disposed in said piston chamber for reciprocationtherein and impaction against said drill bit,

(f) a fluid control valve disposed in said casing,

(g) means for conducting the pressurized fiuid to said fiuid controlvalve,

(h) first passage means communicating at one end with said `controlvalve and at the other end with an end portion of the piston chamber,

(i) second passage means communicating at one end with said controlvalve and at the other end with the opposite end of said piston chamber,

(j) said control valve operative to alternately privide kfor the fiow ofthe-pressurized fiuid through said first and said second passage meansso as to effect the reciprocation of said hammer and thereby cause thelatter to intermittently impact against said drill bit, and

(k) means for supporting said casing in the hole being bored.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS Benjamin 175-100 Harris 175-*296 Fisher 175--92 Ortloff175-92 3,051,134 8/1962 Lincoln 173-78 3,084,673 4/1963 Sears 173-783,162,251 12/1964 Bassinger 173--78 5 CHARLES E. OCONNELL, PrimaryExaminer` JAMES A. LEPPINK, Examiner.

1. A CORE DRILL COMPRISING: AN ELONGATED CASING; A DRILL BIT MOUNTEDWITHIN ONE END OF SAID CASING FOR ROTATION WITH SAID CASING AND LIMITEDAXIAL MOVEMENT RELATIVE TO SAID CASING; SAID CASING BEING DIMENSIONED TOFOLLOW SAID DRILL BIT DOWN A HOLE BEING DRILLED; TUBULAR MEANS MOUNTEDWITHIN SAID CASING TO PROVIDE A CONTINUOUSLY UNOBSTRUCTED PASSAGEBETWEEN THE DRILL BIT AND THE TOP OF SAID CASING AND DIMENSIONED TO BESPACED FROM SAID CASING TO DEFINE AN ANNULAR SPACE; PISTON MEANS MOUNTEDFOR AXIAL MOVEMENT WITHIN SAID ANNULAR SPACE; PASSAGE MEANS FORDELIVERING PRESSURIZED FLUID TO SAID PISTON MEANS; AND ANNULAR VALVEMEANS DISPOSED WITHIN SAID ANNULAR SPACE FOR CONTROLLING THE FLOW OFPRESSURIZED FLUID TO OPPOSITE SIDES OF SAID PISTON MEANS TO CAUSE SAIDPISTON MEANS TO DELIVER AN IMPACT TO SAID DRILL BIT.